/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the  "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id$
 */
package wx.xml.xalan.xpath.compiler;

import java.util.HashMap;

import javax.xml.transform.TransformerException;

import wx.xml.xalan.xpath.functions.Function;

/**
 * The function table for XPath.
 */
public class FunctionTable {

    /**
     * The 'current()' id.
     */
    public static final int FUNC_CURRENT = 0;

    /**
     * The 'last()' id.
     */
    public static final int FUNC_LAST = 1;

    /**
     * The 'position()' id.
     */
    public static final int FUNC_POSITION = 2;

    /**
     * The 'count()' id.
     */
    public static final int FUNC_COUNT = 3;

    /**
     * The 'id()' id.
     */
    public static final int FUNC_ID = 4;

    /**
     * The 'key()' id (XSLT).
     */
    public static final int FUNC_KEY = 5;

    /**
     * The 'local-name()' id.
     */
    public static final int FUNC_LOCAL_PART = 7;

    /**
     * The 'namespace-uri()' id.
     */
    public static final int FUNC_NAMESPACE = 8;

    /**
     * The 'name()' id.
     */
    public static final int FUNC_QNAME = 9;

    /**
     * The 'generate-id()' id.
     */
    public static final int FUNC_GENERATE_ID = 10;

    /**
     * The 'not()' id.
     */
    public static final int FUNC_NOT = 11;

    /**
     * The 'true()' id.
     */
    public static final int FUNC_TRUE = 12;

    /**
     * The 'false()' id.
     */
    public static final int FUNC_FALSE = 13;

    /**
     * The 'boolean()' id.
     */
    public static final int FUNC_BOOLEAN = 14;

    /**
     * The 'number()' id.
     */
    public static final int FUNC_NUMBER = 15;

    /**
     * The 'floor()' id.
     */
    public static final int FUNC_FLOOR = 16;

    /**
     * The 'ceiling()' id.
     */
    public static final int FUNC_CEILING = 17;

    /**
     * The 'round()' id.
     */
    public static final int FUNC_ROUND = 18;

    /**
     * The 'sum()' id.
     */
    public static final int FUNC_SUM = 19;

    /**
     * The 'string()' id.
     */
    public static final int FUNC_STRING = 20;

    /**
     * The 'starts-with()' id.
     */
    public static final int FUNC_STARTS_WITH = 21;

    /**
     * The 'contains()' id.
     */
    public static final int FUNC_CONTAINS = 22;

    /**
     * The 'substring-before()' id.
     */
    public static final int FUNC_SUBSTRING_BEFORE = 23;

    /**
     * The 'substring-after()' id.
     */
    public static final int FUNC_SUBSTRING_AFTER = 24;

    /**
     * The 'normalize-space()' id.
     */
    public static final int FUNC_NORMALIZE_SPACE = 25;

    /**
     * The 'translate()' id.
     */
    public static final int FUNC_TRANSLATE = 26;

    /**
     * The 'concat()' id.
     */
    public static final int FUNC_CONCAT = 27;

    /**
     * The 'substring()' id.
     */
    public static final int FUNC_SUBSTRING = 29;

    /**
     * The 'string-length()' id.
     */
    public static final int FUNC_STRING_LENGTH = 30;

    /**
     * The 'system-property()' id.
     */
    public static final int FUNC_SYSTEM_PROPERTY = 31;

    /**
     * The 'lang()' id.
     */
    public static final int FUNC_LANG = 32;

    /**
     * The 'function-available()' id (XSLT).
     */
    public static final int FUNC_EXT_FUNCTION_AVAILABLE = 33;

    /**
     * The 'element-available()' id (XSLT).
     */
    public static final int FUNC_EXT_ELEM_AVAILABLE = 34;

    /**
     * The 'unparsed-entity-uri()' id (XSLT).
     */
    public static final int FUNC_UNPARSED_ENTITY_URI = 36;

    // Proprietary

    /**
     * The 'document-location()' id (Proprietary).
     */
    public static final int FUNC_DOCLOCATION = 35;
    /**
     * Number of built in functions.  Be sure to update this as
     * built-in functions are added.
     */
    private static final int NUM_BUILT_IN_FUNCS = 37;
    /**
     * Number of built-in functions that may be added.
     */
    private static final int NUM_ALLOWABLE_ADDINS = 30;
    /**
     * The function table.
     */
    private static Class m_functions[];
    /**
     * Table of function name to function ID associations.
     */
    private static HashMap m_functionID = new HashMap();

    static {
        m_functions = new Class[NUM_BUILT_IN_FUNCS];
        m_functions[FUNC_CURRENT] = wx.xml.xalan.xpath.functions.FuncCurrent.class;
        m_functions[FUNC_LAST] = wx.xml.xalan.xpath.functions.FuncLast.class;
        m_functions[FUNC_POSITION] = wx.xml.xalan.xpath.functions.FuncPosition.class;
        m_functions[FUNC_COUNT] = wx.xml.xalan.xpath.functions.FuncCount.class;
        m_functions[FUNC_ID] = wx.xml.xalan.xpath.functions.FuncId.class;
        m_functions[FUNC_KEY] =
            wx.xml.xalan.xalan.templates.FuncKey.class;
        m_functions[FUNC_LOCAL_PART] =
            wx.xml.xalan.xpath.functions.FuncLocalPart.class;
        m_functions[FUNC_NAMESPACE] =
            wx.xml.xalan.xpath.functions.FuncNamespace.class;
        m_functions[FUNC_QNAME] = wx.xml.xalan.xpath.functions.FuncQname.class;
        m_functions[FUNC_GENERATE_ID] =
            wx.xml.xalan.xpath.functions.FuncGenerateId.class;
        m_functions[FUNC_NOT] = wx.xml.xalan.xpath.functions.FuncNot.class;
        m_functions[FUNC_TRUE] = wx.xml.xalan.xpath.functions.FuncTrue.class;
        m_functions[FUNC_FALSE] = wx.xml.xalan.xpath.functions.FuncFalse.class;
        m_functions[FUNC_BOOLEAN] = wx.xml.xalan.xpath.functions.FuncBoolean.class;
        m_functions[FUNC_LANG] = wx.xml.xalan.xpath.functions.FuncLang.class;
        m_functions[FUNC_NUMBER] = wx.xml.xalan.xpath.functions.FuncNumber.class;
        m_functions[FUNC_FLOOR] = wx.xml.xalan.xpath.functions.FuncFloor.class;
        m_functions[FUNC_CEILING] = wx.xml.xalan.xpath.functions.FuncCeiling.class;
        m_functions[FUNC_ROUND] = wx.xml.xalan.xpath.functions.FuncRound.class;
        m_functions[FUNC_SUM] = wx.xml.xalan.xpath.functions.FuncSum.class;
        m_functions[FUNC_STRING] = wx.xml.xalan.xpath.functions.FuncString.class;
        m_functions[FUNC_STARTS_WITH] =
            wx.xml.xalan.xpath.functions.FuncStartsWith.class;
        m_functions[FUNC_CONTAINS] = wx.xml.xalan.xpath.functions.FuncContains.class;
        m_functions[FUNC_SUBSTRING_BEFORE] =
            wx.xml.xalan.xpath.functions.FuncSubstringBefore.class;
        m_functions[FUNC_SUBSTRING_AFTER] =
            wx.xml.xalan.xpath.functions.FuncSubstringAfter.class;
        m_functions[FUNC_NORMALIZE_SPACE] =
            wx.xml.xalan.xpath.functions.FuncNormalizeSpace.class;
        m_functions[FUNC_TRANSLATE] =
            wx.xml.xalan.xpath.functions.FuncTranslate.class;
        m_functions[FUNC_CONCAT] = wx.xml.xalan.xpath.functions.FuncConcat.class;
        m_functions[FUNC_SYSTEM_PROPERTY] =
            wx.xml.xalan.xpath.functions.FuncSystemProperty.class;
        m_functions[FUNC_EXT_FUNCTION_AVAILABLE] =
            wx.xml.xalan.xpath.functions.FuncExtFunctionAvailable.class;
        m_functions[FUNC_EXT_ELEM_AVAILABLE] =
            wx.xml.xalan.xpath.functions.FuncExtElementAvailable.class;
        m_functions[FUNC_SUBSTRING] =
            wx.xml.xalan.xpath.functions.FuncSubstring.class;
        m_functions[FUNC_STRING_LENGTH] =
            wx.xml.xalan.xpath.functions.FuncStringLength.class;
        m_functions[FUNC_DOCLOCATION] =
            wx.xml.xalan.xpath.functions.FuncDoclocation.class;
        m_functions[FUNC_UNPARSED_ENTITY_URI] =
            wx.xml.xalan.xpath.functions.FuncUnparsedEntityURI.class;
    }

    static {
        m_functionID.put(Keywords.FUNC_CURRENT_STRING,
            new Integer(FunctionTable.FUNC_CURRENT));
        m_functionID.put(Keywords.FUNC_LAST_STRING,
            new Integer(FunctionTable.FUNC_LAST));
        m_functionID.put(Keywords.FUNC_POSITION_STRING,
            new Integer(FunctionTable.FUNC_POSITION));
        m_functionID.put(Keywords.FUNC_COUNT_STRING,
            new Integer(FunctionTable.FUNC_COUNT));
        m_functionID.put(Keywords.FUNC_ID_STRING,
            new Integer(FunctionTable.FUNC_ID));
        m_functionID.put(Keywords.FUNC_KEY_STRING,
            new Integer(FunctionTable.FUNC_KEY));
        m_functionID.put(Keywords.FUNC_LOCAL_PART_STRING,
            new Integer(FunctionTable.FUNC_LOCAL_PART));
        m_functionID.put(Keywords.FUNC_NAMESPACE_STRING,
            new Integer(FunctionTable.FUNC_NAMESPACE));
        m_functionID.put(Keywords.FUNC_NAME_STRING,
            new Integer(FunctionTable.FUNC_QNAME));
        m_functionID.put(Keywords.FUNC_GENERATE_ID_STRING,
            new Integer(FunctionTable.FUNC_GENERATE_ID));
        m_functionID.put(Keywords.FUNC_NOT_STRING,
            new Integer(FunctionTable.FUNC_NOT));
        m_functionID.put(Keywords.FUNC_TRUE_STRING,
            new Integer(FunctionTable.FUNC_TRUE));
        m_functionID.put(Keywords.FUNC_FALSE_STRING,
            new Integer(FunctionTable.FUNC_FALSE));
        m_functionID.put(Keywords.FUNC_BOOLEAN_STRING,
            new Integer(FunctionTable.FUNC_BOOLEAN));
        m_functionID.put(Keywords.FUNC_LANG_STRING,
            new Integer(FunctionTable.FUNC_LANG));
        m_functionID.put(Keywords.FUNC_NUMBER_STRING,
            new Integer(FunctionTable.FUNC_NUMBER));
        m_functionID.put(Keywords.FUNC_FLOOR_STRING,
            new Integer(FunctionTable.FUNC_FLOOR));
        m_functionID.put(Keywords.FUNC_CEILING_STRING,
            new Integer(FunctionTable.FUNC_CEILING));
        m_functionID.put(Keywords.FUNC_ROUND_STRING,
            new Integer(FunctionTable.FUNC_ROUND));
        m_functionID.put(Keywords.FUNC_SUM_STRING,
            new Integer(FunctionTable.FUNC_SUM));
        m_functionID.put(Keywords.FUNC_STRING_STRING,
            new Integer(FunctionTable.FUNC_STRING));
        m_functionID.put(Keywords.FUNC_STARTS_WITH_STRING,
            new Integer(FunctionTable.FUNC_STARTS_WITH));
        m_functionID.put(Keywords.FUNC_CONTAINS_STRING,
            new Integer(FunctionTable.FUNC_CONTAINS));
        m_functionID.put(Keywords.FUNC_SUBSTRING_BEFORE_STRING,
            new Integer(FunctionTable.FUNC_SUBSTRING_BEFORE));
        m_functionID.put(Keywords.FUNC_SUBSTRING_AFTER_STRING,
            new Integer(FunctionTable.FUNC_SUBSTRING_AFTER));
        m_functionID.put(Keywords.FUNC_NORMALIZE_SPACE_STRING,
            new Integer(FunctionTable.FUNC_NORMALIZE_SPACE));
        m_functionID.put(Keywords.FUNC_TRANSLATE_STRING,
            new Integer(FunctionTable.FUNC_TRANSLATE));
        m_functionID.put(Keywords.FUNC_CONCAT_STRING,
            new Integer(FunctionTable.FUNC_CONCAT));
        m_functionID.put(Keywords.FUNC_SYSTEM_PROPERTY_STRING,
            new Integer(FunctionTable.FUNC_SYSTEM_PROPERTY));
        m_functionID.put(Keywords.FUNC_EXT_FUNCTION_AVAILABLE_STRING,
            new Integer(FunctionTable.FUNC_EXT_FUNCTION_AVAILABLE));
        m_functionID.put(Keywords.FUNC_EXT_ELEM_AVAILABLE_STRING,
            new Integer(FunctionTable.FUNC_EXT_ELEM_AVAILABLE));
        m_functionID.put(Keywords.FUNC_SUBSTRING_STRING,
            new Integer(FunctionTable.FUNC_SUBSTRING));
        m_functionID.put(Keywords.FUNC_STRING_LENGTH_STRING,
            new Integer(FunctionTable.FUNC_STRING_LENGTH));
        m_functionID.put(Keywords.FUNC_UNPARSED_ENTITY_URI_STRING,
            new Integer(FunctionTable.FUNC_UNPARSED_ENTITY_URI));
        m_functionID.put(Keywords.FUNC_DOCLOCATION_STRING,
            new Integer(FunctionTable.FUNC_DOCLOCATION));
    }

    /**
     * The function table contains customized functions
     */
    private Class m_functions_customer[] = new Class[NUM_ALLOWABLE_ADDINS];
    /**
     * Table of function name to function ID associations for customized functions
     */
    private HashMap m_functionID_customer = new HashMap();
    /**
     * The index to the next free function index.
     */
    private int m_funcNextFreeIndex = NUM_BUILT_IN_FUNCS;

    public FunctionTable() {
    }

    /**
     * Return the name of the a function in the static table. Needed to avoid
     * making the table publicly available.
     */
    String getFunctionName(int funcID) {
        if (funcID < NUM_BUILT_IN_FUNCS)
            return m_functions[funcID].getName();
        else
            return m_functions_customer[funcID - NUM_BUILT_IN_FUNCS].getName();
    }

    /**
     * Obtain a new Function object from a function ID.
     *
     * @param which The function ID, which may correspond to one of the FUNC_XXX
     *              values found in {@link wx.xml.xalan.xpath.compiler.FunctionTable}, but may
     *              be a value installed by an external module.
     * @return a a new Function instance.
     * @throws javax.xml.transform.TransformerException if ClassNotFoundException,
     *                                                  IllegalAccessException, or InstantiationException is thrown.
     */
    Function getFunction(int which)
        throws javax.xml.transform.TransformerException {
        try {
            if (which < NUM_BUILT_IN_FUNCS)
                return (Function) m_functions[which].newInstance();
            else
                return (Function) m_functions_customer[
                    which - NUM_BUILT_IN_FUNCS].newInstance();
        } catch (IllegalAccessException ex) {
            throw new TransformerException(ex.getMessage());
        } catch (InstantiationException ex) {
            throw new TransformerException(ex.getMessage());
        }
    }

    /**
     * Obtain a function ID from a given function name
     *
     * @param key the function name in a java.lang.String format.
     * @return a function ID, which may correspond to one of the FUNC_XXX values
     * found in {@link wx.xml.xalan.xpath.compiler.FunctionTable}, but may be a
     * value installed by an external module.
     */
    Object getFunctionID(String key) {
        Object id = m_functionID_customer.get(key);
        if (null == id)
            id = m_functionID.get(key);
        return id;
    }

    /**
     * Install a built-in function.
     *
     * @param name The unqualified name of the function, must not be null
     * @param func A Implementation of an XPath Function object.
     * @return the position of the function in the internal index.
     */
    public int installFunction(String name, Class func) {

        int    funcIndex;
        Object funcIndexObj = getFunctionID(name);

        if (null != funcIndexObj) {
            funcIndex = ((Integer) funcIndexObj).intValue();

            if (funcIndex < NUM_BUILT_IN_FUNCS) {
                funcIndex = m_funcNextFreeIndex++;
                m_functionID_customer.put(name, new Integer(funcIndex));
            }
            m_functions_customer[funcIndex - NUM_BUILT_IN_FUNCS] = func;
        } else {
            funcIndex = m_funcNextFreeIndex++;

            m_functions_customer[funcIndex - NUM_BUILT_IN_FUNCS] = func;

            m_functionID_customer.put(name,
                new Integer(funcIndex));
        }
        return funcIndex;
    }

    /**
     * Tell if a built-in, non-namespaced function is available.
     *
     * @param methName The local name of the function.
     * @return True if the function can be executed.
     */
    public boolean functionAvailable(String methName) {
        Object tblEntry = m_functionID.get(methName);
        if (null != tblEntry)
            return true;
        else {
            tblEntry = m_functionID_customer.get(methName);
            return (null != tblEntry) ? true : false;
        }
    }
}
